What Display should I get ?

[Vesqwi]

I would need your help guys for that one because I have very few information on what to look. All I know for sure at the moment are the current build specs, and some requirements that monitor must have:
FPS and response time are my #1 priority

So here's the build so far:

CPU: i5 2500K or i7 2600K
GPU: AMD Radeon HD 7970 (will crossfire in a year or so, so please consider it's already crossfired)
Hard Drive: SSD SATA3 120/160GB
Pw supply: Corsair HX1050
Memory: 8 GB (2x4) DDR3 1600 MHz
Mobo: ASUS P8Z68-V/GEN3
OS: win 7 64-bit
Case: unknown yet
Cooling: unknown yet
Monitor: ? ? ? ? (Single)

-Single display only (no multi)
-No 3D (Absolutely not required. I don't need that and would prefer not to pay for that feature)
-Refresh Rate: 120 Hz I guess.. but, I wouldn't know why... tell me more why I should go for 120 Hz more than 60Hz
-Resolution: 1920x1080 or 1920x1200 only
-Screen Size: No idea yet, I'll go at a retail store tonight to figure this out. But I think It will be something between 21" and 24", nothing bigger
-No Built-in Speakers/Webcam: (I don't need that and would prefer not to pay for that)

Below are some features I found that could help me choose, but have no idea what they consist of, and whether or not I should consider them or just not worry about:
-Widescreen: ?
-Pixel Pitch: ?
-Display Colors: ?
-Brightness: ?
-Contrast Ratio: ?
-Response Time: ?
-D-Sub: ?
-DVI: ?
-HDCP Support: ?
-IPS ?